Also known as "TENCHIMUYO RYO-OH-KI HEIANMUYO - The AEKA's desirable world."
Make sure to also check out those translator notes at the end of the video, they help explain a lot of these period specific references.
Heian Muyo! was an audio drama that came from the original Time & Space Adventures audio drama, which itself was the brainchild of Tenchi co-creator Hiroki Hayashi and longtime Tenchi scriptwriter, Ryoe Tsukimura.